You have a a very good start. I like the idea of the similarity between creation and destruction--the same type of energy, intelligence, teamwork, organization is needed for each, and yet very different results are obtained.

We see this in Greene's "Destructors" in which the destruction of the beautiful house is carried out through hard work, discipline, teamwork, and planning. Destroying the house was a masterful act. When one reads this story, we wonder what might have happened if these resources were used for creation, instead of destruction. By extension, we can apply the same principle to war. The money, energy, and teamwork needed to win a war is represented on a smaller lever by Trevor and his gang.

Likewise, Lord of the Flies is set during World War 2. And, like Greene's work, the events on the island reflect the paradoxes of war. We see how various items can be used for creation are for destruction depending on who is using them: the fire (signal fire for rescue or weapon); Piggy's glasses (a sign of rational thought or a means for making fire). We also see how easily and quickly boys, or men for that matter, can be tempted to commit savage acts rather than act as civilized human beings.

Both works seem to pose the question as to why people become destroyers. By using children as their main characters, we see how changes in leadership can cause a fragile civilized group to become quite evil.